Information Processing during Face Recognition: The Effects of Familiarity, Inversion, and Morphing on Scanning Fixations

Abstract

Where we make ocular fixations when viewing an object likely reflects interactions between 'external' object properties and internal 'top-down' factors, as our perceptual system tests hypotheses and attempts to make decisions about our environment. These scanning fixation patterns can tell us how and where the visual system gathers information critical to specific tasks. We determined the effects of the internal factors of expertise, experience, and ambiguity on scanning during a face-recognition task, in eight subjects. To assess the effects of expertise, we compared upright with inverted faces, since it is hypothesized that inverted faces do not access an orientation-dependent face-expert processor. To assess the effects of experience, we compared famous with novel faces, as famous faces would have stronger internal representations than anonymous ones. Ambiguity in matching seen and remembered faces was manipulated with morphed faces. We measured three classes of variables: (i) total scanning time and fixations; (ii) the spatial distribution of scanning; and (iii) the sequence of scanning, using first-order Markov matrices for local scan structure and string editing for global scan structure. We found that, with inverted faces, subjects redistributed fixations to the mouth and lower face, and their local and global scan structure became more random. With novel or morphed faces, they scanned the eyes and upper face more. Local scan structure was not affected by familiarity, but global scan structure was least random (most stereotyped) for novel upright faces. We conclude that expertise (upright faces) leads to less lower-face scanning and more predictable global patterns of information gathering. Experience (famous faces) leads to less upper-face scanning and more idiosyncratic global scan structures, suggesting a superseding influence of facial memories. With morphed faces, subjects return to the upper face to resolve ambiguity, implying a greater importance of this region in face recognition.

Early sensitivity for eyes within faces: A new neuronal account of holistic and featural processing

“…This would explain the narrowing of the perceptual field in inverted faces for which features have to be processed sequentially and independently because of the loss of holistic processing (Rossion, 2009). This featural processing requires viewers to change their face scanning pattern toward more fixations on specific features (Barton et al, 2006;Hills et al, 2012) in order to collect all relevant facial information to do the task at hand (e.g. recognize the identity).…”

“…Eye tracking studies suggest that regardless of task and initial fixation position, participants tend to fixate on or close to the eye region (e.g. Arizpe et al, 2012;Barton et al, 2006;Janik et al, 1978). Eyes are also the most attended feature regardless of face familiarity (Heisz & Shore, 2008) and this preference is seen in infants (Maurer, 1985), with a clear sensitivity to gaze direction already present at birth (Batki et al, 2000).…”

Dog owners show experience-based viewing behaviour in judging dog face approachability

“…eyes, nose and mouth). A few eye-tracking studies have revealed that, in comparison with unfamiliar faces, viewing of familiar (famous, familiarized or personally familiar) faces is associated with fewer fixations and a shorter scanning duration (Barton, Radcliffe, Cherkasova, Edelman, & Intriligator, 2006;Heisz & Shore, 2008), or is accompanied by directing sequential fixations to different local facial regions (van Belle, Ramon, Lefèvre, & Rossion, 2010).…”

“…For human faces, the judgement of approachability corresponds closely to trustworthiness/valence rating (Vernon et al, 2014), and the perceived facial expression is crucial for forming an impression of approachability (Willis, Palermo, & Burke, 2011;Vernon et al, 2014). Considering that humans would name familiar faces faster than unfamiliar ones (Bar & Bierderman, 1998) and demonstrate proficient gaze pattern in the viewing of more-experienced familiar faces (Barton et al, 2006;Heisz & Shore, 2008), we hypothesized that dog-owners may use less viewing time and adopt a more 'efficient' gaze strategy (e.g., fewer number of fixations and fixation allocation at task-relevant informative facial regions) to judge the approachability of dog faces.…”

The effect of varying talker identity and listening conditions on gaze behavior during audiovisual speech perception

“…There is no significant effect of talker variability on either the overall number of fixations or the median duration of fixations (p> .05). Detailed results for each region of interest (ROI) are presented below for the overall number of fixations and fixation durations, and for the number of first and second fixations in each trial.In previous studies looking at gaze behavior during face perception, specifically in studies of audiovisual speech perception (Everdell, Marsh, Yurick, Munhall & Paré, 2007; VatikiotisBateson et al, 1998;Paré et al, 2003) and identity judgment (Henderson et al, 2005;Barton et al, 2006;Althoff & Cohen, 1999), there is a preference to fixate the talker's right eye more often than the left eye. We wanted to see if this preference to fixate the right eye also occurred in the current study.…”